Mixture of grafted polyamide-block and flexible polyolefin copolymers

Abstract

The invention concerns a mixture comprising by weight, the total being 100%, 1 to 100% if a polyamide block copolymer consisting of a basic polyolefin chain and on an average at least a polyamide graft wherein: the grafts are fixed to the basic chain by the radicals of an unsaturated monomer (X) having a function capable of reacting with a polyamide with amine terminal, the radicals of the unsaturated monomer (X) are fixed to the basic chain by grafting or copolymerization from its double bond; 99 to 0% of a flexible polyolefin with elastic modulus in flexure less than 50 MPa at 23° C. and having a crystalline melting point ranging between 60° C. and 100° C. Said mixtures are useful for making films, tanks, geomembrane protective fabrics produced by extrusion, products obtained by calendering, thermocladding/forming, protective films for electric cables and skins using slush molding technique.

1. A polymeric blend consisting essentially of, by weight, the total being 100%:
 1 to less than 100% of a polyamide graft copolymer consisting essentially of a polyolefin backbone and on average at least one polyamide graft per said polyolefin backbone, in which copolymer: 
 the grafts are attached to the backbone by the residues of an unsaturated monomer (X) having a functional group capable of reacting with an amine-terminated polyamide,  
 the residues of the unsaturated monomer (X) are attached to the backbone by grafting or copolymerization from its double bond; and  
 
 99 to above 0% of a flexible polyolefin having an elastic flexural modulus of less than 150 MPa at 23° C. and a crystalline melting point between 60° C. and 100° C., said flexible polyolefin being an olefin homopolymer or a copolymer of at least one alpha-olefin and of at least one copolymerizable monomer being of a different alpha-olefin, an ester of an unsaturated carboxylic acid, a vinyl ester of a saturated carboxylic acid, an unsaturated epoxide, an unsaturated carboxylic acid or salt thereof or anhydride thereof, or a diene, said polymeric blend being characterized by an elastic modulus plateau above the melting point of the flexible polyolefin.  
 
     
     
       2. A blend as claimed in  claim 1 , wherein the flexible polyolefin comprises an ethylene/alkyl (meth)acrylate copolymer. 
     
     
       3. A blend as claimed in  claim 2 , wherein X comprises an unsaturated carboxylic acid anhydride. 
     
     
       4. A blend as claimed in  claim 3 , containing on average at least 1.3 mol of X attached to the polyolefin backbone. 
     
     
       5. A blend as claimed in  claim 4 , wherein the at least one polyamide graft comprises at least one homopolymer of at least one monomer selected from the group consisting of caprolactam residues, 11-aminoundecanoic acid residues, dodecylactam residues, and copolyamides of residues chosen from at least two of the three above monomers. 
     
     
       6. A blend as claimed in  claim 5 , having proportions by weight of 5 to 50% polyamide graft copolymer per 95 to 50% of flexible polyolefin. 
     
     
       7. A blend according to  claim 2 , wherein the ethylene/alkyl (meth)acrylate copolymer comprises 3-35% by weight of (meth)acrylate. 
     
     
       8. An adhesive, consisting essentially of a blend as claimed in  claim 7 . 
     
     
       9. An adhesive as claimed in  claim 8 , in powder form. 
     
     
       10. A blend as claimed in  claim 7 , wherein the polyolefin backbone containing X comprises a member selected from the group consisting of ethylene/maleic anhydride and ethylene/alkyl (meth)acrylate/maleic anhydride copolymers. 
     
     
       11. A blend as claimed in  claim 1 , wherein X comprises an unsaturated carboxylic acid anhydride. 
     
     
       12. A blend as claimed in  claim 11 , wherein the polyolefin backbone containing X is chosen from ethylene/maleic anhydride and ethylene/alkyl (meth)acrylate/maleic anhydride copolymers. 
     
     
       13. A blend as claimed in  claim 1 , containing on average at least 1.3 mol of X attached to the polyolefin backbone. 
     
     
       14. A blend as claimed in  claim 13 , containing on average between 1.3 and 10 mol of X attached to the polyolefin backbone. 
     
     
       15. A blend as claimed in  claim 1 , wherein the at least one polyamide graft comprises at least one homopolymer of at least one monomer selected from the group consisting of caprolactam residues, 11-aminoundecanoic acid residues, dodecylactam residues, and copolyamides of residues chosen from at least two of the three above monomers. 
     
     
       16. A blend as claimed in  claim 1 , wherein the polyamide grafts have a molar mass between 1000 and 5000 g/mol. 
     
     
       17. A blend as claimed in  claim 1  having proportions by weight of 5 to 50% polyamide-block graft copolymer per 95 to 50% of flexible polyolefin. 
     
     
       18. An adhesive, consisting essentially of a blend as claimed in  claim 1 . 
     
     
       19. An adhesive as claimed in  claim 18 , in powder form. 
     
     
       20. A film, comprising a blend as claimed in  claim 1 . 
     
     
       21. A tarpaulin or geomembrane, comprising at least one layer of a blend as claimed in  claim 1 . 
     
     
       22. A product obtained by calendering a blend as claimed in  claim 1 . 
     
     
       23. A power cable or telecommunications cable, comprising a protective layer comprising a blend as claimed in  claim 1 . 
     
     
       24. A process comprising slush molding a blend according to  claim 1  in powder form.